Bulletin d’avalanche

East Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Tue
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré last year. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

A recent windy storm has left reactive slabs of wind-drifted snow in exposed terrain across the zone. These are most concerning in upper elevation terrain and around some wind-exposed middle elevations. Wet snow instabilities may materialize on south-facing slopes during sunny periods. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    Several inches of new snow, paired with strong wind speeds, created reactive slabs on Sunday. With wind speeds staying strong enough to move snow through Sunday night, expect continued reactivity at upper and some middle-elevation terrain on Monday. 

    Look for these slabs to be larger and more widespread as you gain elevation into the wind zone. Blowing snow and fresh cornice formation often point toward areas with wind loading and elevated danger. Look for the tell-tale signs of a wind-affected surface, such as ripples or dunes. Cracking or collapsing indicates you have found an unstable slab, directing you to a lower-angle slope. You can easily reduce your exposure to this problem by sticking to more sheltered terrain less than 35 degrees that offers good powder riding. 

    Additional Discussion:

    Lingering storm slab instabilities may exist in steep or unsupported terrain closer to the Cascade crest. If you plan on traveling in these western parts of the zone, approach steep, open terrain with some suspicion. You can use a small test slope or simple hand pits to help you gauge the reactivity of the recent storm snow. 

    (1/6/2025)

    Steer around wind-loaded features greater than 35 degrees if you notice ripples or cracking at the snow surface. 

    Photo: Joe Dellaporta

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Partly cloudy skies may supply just enough filtered sunshine to create wet snow instabilities on solar aspects. Anytime the sun pokes out after fresh snowfall (especially in March), expect some level of wet snow instabilities to form. Pay attention to your aspect, timing, and the snow surfaces around you. Consider moving to a shader aspect once you notice rollerballs shedding or sticky, gloppy surfaces under your feet or machine. 

    (2/20/2025)

    An example of rollerballs in fresh snow accumulations. 

    Photo: Dallas Glass

Avalanche Discussion

The storm that brought a nice refresh of 5-11 inches of new snow across the zone in the past days is moving out of the region. In typical Cascade fashion, locations closer to the Crest received more favorable snow totals, while the eastern Wenatchee mountains picked up 4-6 inches of new snow. The common theme across all weather stations was the strong SW winds. Unsurprisingly, observers from Salmon La Sac (observation here) to Mission Ridge (observation here)  reported sensitive drifts and skier-triggered wind slabs. 

Monday is shaping up to be a fairly pleasant day in the mountains before clouds start filtering back in ahead of our next system.  However, keep in mind that we’re coming out of a windy storm and a period with limited observations, especially at upper elevations. Ease into the terrain with an assessment mindset and be suspicious of steeper, open slopes that may have collected slabs of drifted snow. 

Persistent slabs continue to be an issue in the adjacent zone to the north. While we’ve put this problem to bed in the East Central, it’s worth considering in very northern portions or more far-flung parts of the zone. To reduce your risk, you can default to simpler terrain that is planar and short.

You can help us gather more data by submitting an observation HERE or via the Avy App.

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